The UpdatePipelineStatus operation pauses or reactivates a pipeline,
so that the pipeline stops or restarts the processing of jobs.

Changing the pipeline status is useful if you want to cancel one or
more jobs. You can't cancel jobs after Elastic Transcoder has started
processing them; if you pause the pipeline to which you submitted the
jobs, you have more time to get the job IDs for the jobs that you want
to cancel, and to send a CancelJob request.